Implementing IPv6 for Network Management

First Published: June 7, 2001

Last Updated: July 20, 2011

This document describes the concepts and commands used to manage Cisco applications over IPv6 and to implement IPv6 for network management. The copy, ping, telnet, and traceroute commands were modified to provide IPv6 management capability. Secure Shell (SSH) has been enhanced to provide support for IPv6 addresses that enable a Cisco router to accept and establish secure, encrypted connections with remote IPv6 nodes over an IPv6 transport.

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest feature information and caveats, see the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the "Feature Information for Implementing IPv6 for Network Management" section.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn.An account on Cisco.com is not required.

Prerequisites for Implementing IPv6 for Network Management

•By default, IPv6 routing is disabled in the Cisco IOS software. To enable IPv6 routing, you must first enable the forwarding of IPv6 traffic globally on the router and then you must assign IPv6 addresses to individual interfaces in the router. At least one interface must have IPv6 configured.

•To enable Telnet access to a router, you must create a vty interface and password.

•This document assumes that you are familiar with IPv4. Refer to the publications referenced in the "Additional References" section for IPv4 configuration and command reference information.

Information About Implementing IPv6 for Network Management

Telnet Access over IPv6

The Telnet client and server in the Cisco IOS software support IPv6 connections. A user can establish a Telnet session directly to the router using an IPv6 Telnet client, or an IPv6 Telnet connection can be initiated from the router. A vty interface and password must be created in order to enable Telnet access to an IPv6 router.

TFTP File Downloading for IPv6

IPv6 supports TFTP file downloading and uploading using the copy command. The copy command accepts a destination IPv6 address or IPv6 hostname as an argument and saves the running configuration of the router to an IPv6 TFTP server, as follows:

Note In Cisco IOS Release 12.2(8)T or later releases, a literal IPv6 address specified with a port number must be enclosed in square brackets ([ ]) when the address is used in TFTP source or destination URLs; a literal IPv6 address specified without a port number need not be enclosed in square brackets. Refer to RFC 2732, Format for Literal IPv6 Addresses in URLs, for more information on the use of square brackets with literal IPv6 address in URLs.

ping and traceroute Commands in IPv6

The ping command accepts a destination IPv6 address or IPv6 hostname as an argument and sends Internet Control Message Protocol version 6 (ICMPv6) echo request messages to the specified destination. The ICMPv6 echo reply messages are reported on the console. Extended ping functionality is also supported in IPv6.

The traceroute command accepts a destination IPv6 address or IPv6 hostname as an argument and will generate IPv6 traffic to report each IPv6 hop used to reach the destination address.

SSH over an IPv6 Transport

SSH in IPv6 functions the same and offers the same benefits as SSH in IPv4—the SSH Server feature enables an SSH client to make a secure, encrypted connection to a Cisco router and the SSH Client feature enables a Cisco router to make a secure, encrypted connection to another Cisco router or to any other device running an SSH server. IPv6 enhancements to SSH consist of support for IPv6 addresses that enable a Cisco router to accept and establish secure, encrypted connections with remote IPv6 nodes over an IPv6 transport.

SNMP over an IPv6 Transport

Simple Network Management Protocol (SNMP) can be configured over IPv6 transport so that an IPv6 host can perform SNMP queries and receive SNMP notifications from a device running Cisco IOS IPv6. The SNMP agent and related MIBs have been enhanced to support IPv6 addressing.

SNMP for IPv6 provides 3DES and AES are provided for message encryption.

Cisco IOS IPv6 MIBs

Cisco has long supported IP-MIB and IP-FORWARD-MIB in IPv4. CISCO-IETF-IP-MIB and CISCO-IETF-IP-FORWARDING-MIB are IPv6 MIBs that are defined as being protocol-independent, but are implemented only for IPv6 objects and tables. In Cisco IOS Release 12.2(33)SRC, IP-MIB and IP-FORWARD-MIB were updated to RFC 4293 and RFC 4292 standards, as follows:

•The upgrade is backward-compatible; all IP-MIB and IP-FORWARD-MIB objects and tables still appear.

•IP-MIB and IP-FORWARD-MIB include definitions of new IPv6-only, IPv4-only, and protocol-version independent (PVI) objects and tables. However, support is added only for the new IPv6-only and the new IPv6 part of the PVI objects and tables in these MIBs.

MIBs Supported for IPv6

•CISCO-IETF-IP-FORWARDING-MIB (not available as of Cisco IOS Release 12.2(33)SRC)

•CISCO-IETF-IP-MIB (not available as of Cisco IOS Release 12.2(33)SRC)

•IP-FORWARD-MIB

•IP-MIB

•ENTITY-MIB

•NOTIFICATION-LOG-MIB

•SNMP-TARGET-MIB

CISCO-CONFIG-COPY-MIB and CISCO-FLASH-MIB support IPv6 addressing when either TFTP, remote copy protocol (rcp), or FTP is used.

The following MIB was added for the IPv6 over SNMP support feature:

•CISCO-SNMP-TARGET-EXT-MIB

The following MIBs have been modified for the IPv6 over SNMP support feature:

•CISCO-FLASH-MIB

•CISCO-CONFIG-MAN-MIB

•CISCO-CONFIG-COPY-MIB

Cisco IOS IPv6 Embedded Management Components

This section describes Cisco IOS embedded management components that have IPv6-compliant operability in IPv6 and hybrid IPv6 and IPv4 networks. The Cisco IOS embedded management components described in the following sections have IPv6 capabilities:

As of Cisco IOS Release 12.4(4)T and 12.2(33)SRC, this feature is backward-compatible with existing IPv4 and new IPv6 addresses and hostnames.

CNS Agents

IPv6 addressing is supported in the Cisco Networking Services (CNS) subsystem. CNS is a foundation technology for linking users to networking services and provides the infrastructure for the automated configuration of large numbers of network devices. Many IPv6 networks are complex, with many devices, and each device must be configured individually. When standard configurations do not exist or have been modified, the time involved in initial installation and subsequent upgrading is considerable. Internet service providers (ISPs) need a method for sending out partial configurations to introduce new services.

To address all these issues, CNS was designed to provide "plug-and-play" network services using a central directory service and distributed agents. CNS features include CNS agents and a flow-through provisioning structure. CNS flow-through provisioning uses the CNS configuration and event agents to provide an automated workflow, eliminating the need for an onsite technician.

IPv6 addressing supports the CNS agents described in the following sections:

CNS Configuration Agent

The CNS configuration agent is involved in the initial configuration and subsequent partial configurations on a Cisco IOS device. The configuration agent uses a CNS configuration engine to provide methods for automating initial Cisco IOS device configurations, incremental configurations, and synchronized configuration updates, and the configuration engine reports the status of the configuration load as an event to which a network monitoring or workflow application can subscribe.

CNS Event Agent

The CNS event agent provides a transport connection to the CNS event bus for all other CNS agents. No event can be sent to the router by the configuration engine until the CNS event agent is operational and has successfully built a connection between the configuration engine and the router.

CNS EXEC Agent

The CNS EXEC agent allows a remote application to execute a CLI command in EXEC mode on a Cisco IOS device by sending an event message that contains the command.

CNS Image Agent

Administrators maintaining large networks of Cisco IOS devices need an automated mechanism to load image files onto large numbers of remote devices. Network management applications are useful to determine which images to run and how to manage images received from the Cisco online software center. Other image distribution solutions do not scale to cover thousands of devices and cannot distribute images to devices behind a firewall or using Network Address Translation (NAT). The CNS image agent enables the managed device to initiate a network connection and request an image download allowing devices using NAT, or behind firewalls, to access the image server.

The CNS image agent can be configured to use the CNS event bus. To use the CNS event bus, the CNS event agent must be enabled and connected to the CNS event gateway in the CNS Configuration Engine. The CNS image agent can also use an HTTP server that understands the CNS image agent protocol. Deployment of CNS image agent operations can use both the CNS event bus and an HTTP server.

For further information about CNS agents, see "Cisco Networking Services" in the Cisco IOS Network Management Configuration Guide.

HTTP(S) IPv6 Support

This feature enhances the HTTP(S) client and server to support IPv6 addresses. The HTTP server in Cisco IOS software can service requests from both IPv6 and IPv4 HTTP clients. The HTTP client in Cisco IOS software supports sending requests to both IPv4 and IPv6 HTTP servers. When you use the HTTP client, URLs with literal IPv6 addresses must be formatted using the rules listed in RFC 2732.

NETCONF

The Network Configuration Protocol (NETCONF) defines a mechanism through which a network device can be managed, configuration data information can be retrieved, and new configuration data can be uploaded and manipulated. NETCONF uses XML-based data encoding for the configuration data and protocol messages.

SOAP Message Format

Using the Service-Oriented Access Protocol (SOAP) protocol provides a way to format the layout of CNS messages in a consistent manner. SOAP is a protocol intended for exchanging structured information in a decentralized, distributed environment. SOAP uses XML technologies to define an extensible messaging framework that provides a message format that can be exchanged over a variety of underlying protocols.

Within the SOAP message structure, there is a security header that enables CNS notification messages to authenticate user credentials.

IP SLAs for IPv6

Cisco IOS IP Service Level Agreements (SLAs) are a portfolio of technology embedded in most devices that run Cisco IOS software that allows Cisco customers to analyze IPv6 service levels for IPv6 applications and services, to increase productivity, to lower operational costs, and to reduce the frequency of network outages. IP SLAs uses active traffic monitoring—the generation of traffic in a continuous, reliable, and predictable manner—for measuring network performance.

The following Cisco IOS IP SLAs are supported for IPv6:

•Internet Control Message Protocol (ICMP) echo operation—Used to monitor end-to-end response time between a Cisco router and devices using IPv4 or IPv6. ICMP Echo is useful for troubleshooting network connectivity issues.

•TCP connect operation—Used to measure the response time taken to perform a TCP Connect operation between a Cisco router and devices using IPv4 or IPv6.

•User Datagram Protocol (UDP) echo operation—Used to monitor end-to-end response time between a Cisco router and devices using IPv4 or IPv6.

Note RSA is the public key cryptographic system developed by Ron Rivest, Adi Shamir, and Leonard Adelman. RSA keys come in pairs: one public key and one private key.

•A user authentication mechanism for local or remote access is configured on your router.

Restrictions

The basic restrictions for SSH over an IPv4 transport listed in "Configuring Secure Shell" in the Cisco IOS Security Configuration Guide apply to SSH over an IPv6 transport. In addition to the restrictions listed in that chapter, the use of locally stored usernames and passwords is the only user authentication mechanism supported by SSH over an IPv6 transport; the TACACS+ and RADIUS user authentication mechanisms are not supported over an IPv6 transport.

Note To authenticate SSH clients, configure TACACS+ or RADIUS over an IPv4 transport and then connect to an SSH server over an IPv6 transport.

•You can specify the timeout in seconds, not to exceed 120 seconds. The default is 120. This setting applies to the SSH negotiation phase. Once the EXEC session starts, the standard timeouts configured for the vty apply.

By default, five vty lines are defined (0-4); therefore, five terminal sessions are possible. After the SSH executes a shell, the vty timeout starts. The vty timeout defaults to 10 minutes.

•You can also specify the number of authentication retries, not to exceed five authentication retries. The default is three.

Configuring an SNMP Notification Server over IPv6

Use an SNMP community string to define the relationship between the SNMP manager and the agent. The community string acts like a password to regulate access to the agent on the router. Optionally, you can specify one or more of the following characteristics associated with the string:

•An access list of IP addresses of the SNMP managers that are permitted to use the community string to gain access to the agent.

•A MIB view, which defines the subset of all MIB objects accessible to the given community.

•Read and write or read-only permission for the MIB objects accessible to the community.

You can configure one or more community strings. To remove a specific community string, use the no snmp-server communitycommand.

•Specifies whether you want the SNMP notifications sent as traps or informs, the version of SNMP to use, the security level of the notifications (for SNMPv3), and the recipient (host) of the notifications.

Note You cannot configure a remote user for an address without first configuring the engine ID for that remote host. This is a restriction imposed in the design of these commands; if you try to configure the user before the host, you will receive a warning message and the command will not be executed

Step 8

snmp-server enable traps[notification-type] [vrrp]

Example:

Router(config)# snmp-server enable traps bgp

Enables sending of traps or informs, and specifies the type of notifications to be sent.

•If a notification-type is not specified, all supported notification will be enabled on the router.

•To discover which notifications are available on your router, enter the snmp-server enable traps ? command.

Configuring Cisco IOS IPv6 Embedded Management Components

Most IPv6 embedded management components are enabled automatically when IPv6 is enabled and do not need further configuration. To configure syslog over IPv6 or disable HTTP access to a router, refer to the tasks in the following sections:

Configuration Examples for Implementing IPv6 for Network Management

Examples: Enabling Telnet Access to an IPv6 Router Configuration

The following examples provide information on how to enable Telnet and start a session to or from an IPv6 router. In the following example, the IPv6 address is specified as 2001:DB8:20:1::12, and the hostname is specified as cisco-sj. The show host command is used to verify this information.

Router# configure terminal

Router(config)# ipv6 hostcisco-sj 2001:DB8:20:1::12

Router(config)# end

Router# show host

Default domain is not set

Name/address lookup uses static mappings

Codes:UN - unknown, EX - expired, OK - OK, ?? - revalidate

temp - temporary, perm - permanent

NA - Not Applicable None - Not defined

Host Port Flags Age Type Address(es)

cisco-sj None (perm, OK) 0 IPv6 2001:DB8:20:1::12

To enable Telnet access to a router, create a vty interface and password:

Router(config)# line vty04

password lab

login

To use Telnet to access the router, you must enter the password:

Router# telnet cisco-sj

Trying cisco-sj (2001:DB8:20:1::12)... Open

User Access Verification

Password:

cisco-sj

.

.

.

verification

It is not necessary to use the telnet command. Specifying either the hostname or the address is sufficient, as shown in the following examples:

Router# cisco-sj

or

Router# 2001:DB8:20:1::12

To display the IPv6 connected user (line 130) on the router to which you are connected, use the show users command:

Router# show users

Line User Host(s) Idle Location

* 0 con 0 idle 00:00:00

130 vty 0 idle 00:00:22 8800::3

Note that the address displayed is the IPv6 address of the source of the connection. If the hostname of the source is known (either through a domain name server (DNS) or locally in the host cache), then it is displayed instead:

Router# show users

Line User Host(s) Idle Location

* 0 con 0 idle 00:00:00

130 vty 0 idle 00:02:47 cisco-sj

If the user at the connecting router suspends the session with ^6x and then enters the show sessions command, the IPv6 connection is displayed:

Router# show sessions

Conn Host Address Byte Idle Conn Name

* 1 cisco-sj 2001:DB8:20:1::12 0 0 cisco-sj

The Conn Name field shows the hostname of the destination only if it is known. If it is not known, the output might look similar to the following:

Router# show sessions

Conn Host Address Byte Idle Conn Name

* 1 2001:DB8:20:1::12 2001:DB8:20:1::12 0 0 2001:DB8:20:1::12

Example: Disabling HTTP Access to the Router

In the following example, the show running-config command is used to show that HTTP access is disabled on the router:

Router# show running-config

Building configuration...

!

Current configuration : 1490 bytes

!

version 12.2

!

hostname Router

!

no ip http server

!

line con 0

line aux 0

line vty 0 4

Examples: Configuring an SNMP Notification Server over IPv6

The following example permits any SNMP to access all objects with read-only permission using the community string named public. The router also will send BGP traps to the IPv4 host 172.16.1.111 and IPv6 host 3ffe:b00:c18:1::3/127 using SNMPv1 and to the host 172.16.1.27 using SNMPv2c. The community string named public is sent with the traps.

Router(config)# snmp-servercommunity public

Router(config)# snmp-server enable traps bgp

Router(config)# snmp-server host172.16.1.27 version 2c public

Router(config)# snmp-server host172.16.1.111 version 1 public

Router(config)# snmp-server host3ffe:b00:c18:1::3/127 public

Associate an SNMP Server Group with Specified Views Example

In the following example, the SNMP context A is associated with the views in SNMPv2c group GROUP1 and the IPv6 named access list public2:

Technical Assistance

Description

Link

The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

http://www.cisco.com/cisco/web/support/index.html

Feature Information for Implementing IPv6 for Network Management

Table 1 lists the features in this module and provides links to specific configuration information.

Use Cisco Feature Navigator to find information about platform support and software image support. Cisco Feature Navigator enables you to determine which software images support a specific software release, feature set, or platform. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.

Note Table 1 lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

CNS configuration and event agents use a CNS configuration engine to provide methods for automating initial Cisco IOS device configurations, incremental configurations, and synchronized configuration updates, and the configuration engine reports the status of the configuration load as an event to which a network monitoring or workflow application can subscribe.

The Network Configuration Protocol (NETCONF) defines a simple mechanism through which a network device can be managed, configuration data information can be retrieved, and new configuration data can be uploaded and manipulated.

SSH in IPv6 functions the same and offers the same benefits as SSH in IPv4—the SSH Server feature enables an SSH client to make a secure, encrypted connection to a Cisco router and the SSH Client feature enables a Cisco router to make a secure, encrypted connection to another Cisco router or to any other device running an SSH server.

The Telnet client and server in the Cisco IOS software support IPv6 connections. A user can establish a Telnet session directly to the router using an IPv6 Telnet client, or an IPv6 Telnet connection can be initiated from the router.

Cisco and the Cisco Logo are trademarks of Cisco Systems, Inc. and/or its affiliates in the U.S. and other countries. A listing of Cisco's trademarks can be found at www.cisco.com/go/trademarks. Third party trademarks mentioned are the property of their respective owners. The use of the word partner does not imply a partnership relationship between Cisco and any other company. (1005R)

Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be actual addresses and phone numbers. Any examples, command display output, network topology diagrams, and other figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses or phone numbers in illustrative content is unintentional and coincidental.